Fix rounding error

[steros]

Description

Prices should only rounded to two decimal places in view.

I doubt 2 decimal places is correct here.
If I want a product price of "165" and thus set a base price of "138.6554" with a tax of 19% I get "165.01" because of the rounding to 2 decimal places here.
Setting this to 4 decimal places fixes that issue.

The fact that it is not possible to set a price with 4 decimal places in the backend is another issue that needs to be set separately I suppose.

Manual testing scenarios

1. set a product price of 138.6554
2. set tax to 19%
3. go to checkout cart
4. final price is 165.01 instead of 165.00

[orlangur]

The fact that it is not possible to set a price with 4 decimal places in the backend is another issue that needs to be set separately I suppose.

set a product price of 138.6554

Looks a bit contradictory, isn't it?

Some currencies have two decimals, some three, some even zero. Proposed solution may be suitable for your particular needs but in core there should be something more sophisticated covering many scenarios, see #1240 (comment)

Problem in general is tracked as https://github.com/magento/magento2/issues/10532 I believe.

[steros]

I was going from the point that this is the model not the view. Magento stores prices with 4 decimal places and calculates with them in most places I have seen so far.
The fact that there are currencies with more or less decimals should not be a matter of the model but the view.
There you should be able to set whatever decimals you please.
But the rounding that takes place in the model prevents setting some prices for cases where you need 4 decimals.

[orlangur]

The fact that there are currencies with more or less decimals should not be a matter of the model but the view.

Nope as prices/taxes/etc and corresponding business logic is model responsibility.

The fact that it is not possible to set a price with 4 decimal places in the backend is another issue that needs to be set separately I suppose.

Such changes, if approved, should be done in scope of the same effort. All necessary scenarios needs to be tested in scope of it. Not just take https://travis-ci.org/magento/magento2/jobs/278635465#L897 and change assetions to the new value :)